The present invention relates to a method and apparatus for securely circulating electronic tickets composed of digital information which need to be protected from duplicate redemption or fraud and, more particularly, to a method for circulating, by a general-purpose processing system, electronic tickets with various application-dependent circulation conditions such as issue and transfer conditions.
At present, software, images, news and so forth are already circulated using the Internet and similar electronic communication means, but any other goods that can be encoded as digital information can inherently be delivered or circulated electronically. In service industries, in particular, such a variety of tickets as listed below are circulated as commodities, and they can also be electronically circulated.
(1) Reservation Tickets                Concert ticket, Reserved seat ticket, Plane ticket, Hotel accommodation ticket, Ticket for booking to play tennis.        
(2) Exchange Tickets                Bill of lading, Pawn ticket, Claim ticket, Title deed.        
(3) Order Tickets                Admission-order ticket for a bargain counter, Queuing ticket for a customer to be served at a teller's window, Numbered ticket for medical care.        
(4) Gift Certificates                Gift coupon, Beer coupon, Book coupon, Rice coupon, Restaurant coupon.        
(5) Prepaid Cards                Telephone card, Prepaid card, Transportation pass, Expressway transportation pass.        
(6) Permits                Driver's license, Passport, Gate card.        
The ticket herein mentioned is a representation of the ticket owner's right to claim the services or goods written on the ticket. Such a ticket can be provided in electronic form by encoding the claim contents as digital information and attaching thereto the issuer's signature.
The electronization of the ticket offers an advantage which reduces the costs for issuing and mailing paper tickets. Another advantage is to raise the limitation to the place and time for selling tickets, making it possible to get and use tickets anytime and anywhere. Furthermore, a ticket can be transferred to a friend or acquaintance at a remote place over a network. The electronization of the ticket thus improves its usability. For these reasons, a trend toward the electronization of tickets has become active in recent years.
As for event tickets for concerts, sports games and so on, there already exist dealers who sell electronic tickets over the Internet like e-ticket (http://www.e-ticket.net/), for instance. As regards exchange tickets, too, there are dealers who sells exchange tickets for gold like e-gold (http://www.e-gold.com) of Gold & Silver Reserve, Inc. of the United States. For the electronization of gift coupons and prepaid cards, there have been proposed, for example, a prepaid card model based micropayment system described in S. Glassman, M. Manasse, M. Abadi, P. Gauthier, and P. Sobalvarro, “The Millicent Protocol for Inexpensive Electronic Commerce” (Proceedings of 4th World Wide Web Conference) and another prepaid-card-model-based ticket implementation method described in R. Rivest and Adi Shamir, “Pay Word and MicroMint: Two simple micropayment schemes” (Technical report, MIT, Cambridge, 1996).
Unlike digital contents such as an ordinary image and a sound, the ticket needs to be protected from double spending or similar fraud, and such fraud prevention schemes have been rapidly developed. Several schemes are proposed in the above-mentioned references, but in a reference on electronic cash technology, for example, Peter Wayner, “Digital Cash” (Academic Press Ltd. ISBN 0-12-788772-5), there are summarized methods for secure transfer and transaction of valuable information like electronic cash. In U.S. Pat. Nos. 5,621,797 and 5,557,518 there are proposed methods for secure redemption and transfer of electronic tickets, focusing on a transportation ticket, an event ticket, a communication service access ticket and a permit. Moreover, in Japanese Patent Application Laid-Open Gazette No. 31204/99 there is proposed an electronic ticket system that implements electronic tickets which are difficult to forge and duplicate but whose contents are provable to third parties.
However, these conventional schemes just mentioned above are intended only to protect the electronic ticket from fraud, and they do not propose a general-purpose method for defining a wide variety of electronic tickets nor do they offer a general-purpose processing system for issue, transfer and redeem transactions of diverse electronic tickets. There has not been yet studied any general-purpose electronic ticket circulation control method and apparatus which make it possible to control various circulation conditions such as listed below.                (1) Only qualified dealers or agents are allowed to issue tickets, e.g., lottery tickets and betting tickets.        (2) Tickets are issued (sold) only to qualified users, e.g., student discount transportation pass (that can be issued only to a person with a student identification card).        (3) Only qualified dealers and users are allowed to transfer (sell) tickets, e.g., plane tickets (that only travel agents can transfer).        (4) Only qualified users are allowed to redeem tickets, e.g., expressway tickets (requiring transportation tickets).        (5) Only qualified dealers are allowed to examine tickets, e.g., beer coupons and book coupons.        
As described above, several electronic ticket processing methods and apparatuses have been proposed, but conventional systems are all those dedicated to individual applications. Conventionally, it is necessary, therefore, to develop ticket information readout software, a trading system and so forth for each ticket—this inevitably raises development costs. To solve this problem, there has been a strong demand for a general-purpose scheme of processing a wide variety of electronic tickets, but it has been difficult to implement a general-purpose ticket processing system because of diverse types and properties of electronic tickets.